DESCRIPTION: Latent HIV-1 infection has been recognized as one major obstacle to the development of a curative HIV-1 therapy, however, cellular and viral interaction events that control latent infection are still ill defined. The use of HDAC inhibitors that have been promoted as HIV reactivating drugs in the last years has generated awareness that HIV eradication can and should be examined. However, the success of HDAC inhibitors as HIV-1 reactivating agents has been limited. Key to this application is the realization that the host-cells of latent HIV-1 infection events are actually phenotypically altered in a manner that forces the virus into a latent state and renders the cells unresponsive to stimulation. An anergy-like, unresponsive state of the host T cells would conclusively explain the extraordinary in vivo stability of the latnt viral reservoir despite continuous exposure to cognate antigen. It would also explain recent findings describing that the majority of the latent infection events in ex vivo patient material ar even unresponsive to PHA stimulation. We previously demonstrated the presence of a gate-keeper kinase function that controls latent HIV-1 infection even in the presence of high levels of induced NF-kB activity. Our data now show that phenotypic changes of the host cells go beyond the functionality of individual kinases, but that the activities of entire pathways are altered in latently infected T cells. Kinome profiling revealed novel drug targets that we have already successfully targeted to alter control of latent HIV-1 infection in T cell lines and in primary T cll models of latent HIV infection. We also provide data that CD4 T cells from HIV-1 patients on successful ART are massively altered at the kinomic level. While the kinomic changes are more complex than in T cell lines, there is complete overlap in the affected T cell signaling pathways, a finding that likely explains why some of the findings obtained in T cell lines can be directly transferred into primary T cell models and used to perturb the stability of the latent HIV reservoir. Given this observation, in this application, we propose to generate increasingly detailed kinome profiles of the most relevant memory T cell sub-populations know to host latent HIV-1 infection events using ex vivo T cell material from HIV-1 infected patients and to generate protein-protein interaction networks (PIN) that describe HIV-1 latency control. The generated PINs will then be used to probe identified targets that control latent HIV- 1 infection and to develop novel drug combinations that efficiently trigger HIV-1 reactivation. The goal of this application is to establish a comprehensive model of latent HIV-1 infection that considers the dynamic, bi-directional interactions of the virus with the host-cell at the kinase, transcription factor and possibly chromatin level and to use this knowledge to drive a drug repositioning effort to identify drug combinations that will reverse the unresponsive state of the host T cells, thereby allowing cognate antigen and possible therapeutic stimuli to trigger HIV-1 reactivation. The insights gained from the described studies will provide a blueprint for how to develop efficient HIV-1 reactivating therapeutic strategies based on unexplored molecular drug targets.